If it takes up a large portion of disk space
Remove Windows.old folder from Windows 10
If you’ve tried upgrading your Windows PC and failed a few times due to various annoying reasons, you’ve probably noticed that a large chunk of your disk space is being taken up by a folder called Windows.old.
Windows.old is automatically generated when you perform an installation of Windows with a previous version of the operating system already installed. It creates this Windows.old folder in the root of the Windows partition and stores the files and data of the previous operating system.
If you try to upgrade from Windows Vista to Windows 7 or Windows 7 to Windows 10 and it fails, you can always safely roll back to Windows Vista or 7. The only problem with this is that every time the installation fails, another copy of the previous operating system is copied into Windows.old.
